SQG - Compile SQL to Type-Safe Code | Blog

I Benchmarked 9 Ways to Insert Data Into PostgreSQL From Java. COPY BINARY Won by a Landslide.

Thu, 26 Mar 2026 00:00:00 GMT

TL;DR: We benchmarked 9 different methods of inserting data into PostgreSQL from Java, from naive individual INSERTs to DuckDB-via-Arrow pipelines. COPY BINARY wins decisively at scale: 712K rows/sec for 1M rows — 2x faster than COPY CSV, 5x faster than JDBC batch, and 18x faster than individual INSERTs. The sweet spot for most applications is reWriteBatchedInserts=true (one URL parameter, 2.5x speedup over naive batch). For high-volume ingestion, COPY BINARY via PgBulkInsert is unbeatable.

The Setup

We built a benchmark that simulates an IoT sensor ingestion pipeline — a table with 9 columns covering the interesting PostgreSQL types: UUID, TIMESTAMPTZ, DOUBLE PRECISION, NUMERIC, SMALLINT, BOOLEAN, TEXT, and TEXT[]. One million rows of randomized but deterministic sensor readings (temperature, humidity, pressure, battery level, anomaly flags, location tags).

Each method was warmed up (2 runs), then measured (5 runs, median taken). After every insert, we verified both row count and spot-checked the first and last 10 rows against source data. PostgreSQL 18 via TestContainers. Java 25.

All benchmark code is open source: examples/java-postgres-benchmark.

The Methods

Here’s what we tested, roughly in order of complexity:

1. Individual INSERT (the naive approach)

One executeUpdate() per row, wrapped in a single transaction. This is what most beginners write, and what many ORMs produce. (code)

2. Batch INSERT (`addBatch` / `executeBatch`)

Standard JDBC batching. Accumulate rows with addBatch(), flush with executeBatch(). The driver sends them as individual INSERT statements but pipelines the network calls. (code)

3. Batch INSERT with `reWriteBatchedInserts=true`

Same code as #2, but with one URL parameter added: ?reWriteBatchedInserts=true. The PostgreSQL JDBC driver automatically rewrites individual batched INSERTs into multi-value statements: INSERT INTO t VALUES (...),(...),.... This is the lowest-effort optimization you can make. (code)

4. Multi-value INSERT (hand-crafted)

Manually build INSERT INTO t VALUES (...),(...),(...) ... with chunks of 1,000 rows. The hand-rolled version of what reWriteBatchedInserts does automatically. (code)

5. UNNEST

INSERT INTO t SELECT * FROM unnest($1::uuid[], $2::timestamptz[], ...)

Pass one array per column instead of one parameter per cell. Only 9 parameters regardless of row count, so it avoids PostgreSQL’s 65K parameter limit. Reduces query planning overhead. (code, generated)

6. COPY CSV

PostgreSQL’s COPY ... FROM STDIN WITH (FORMAT CSV) via the JDBC driver’s CopyManager. Build a CSV string in memory, stream it to PostgreSQL. This is the standard “fast path” that most PostgreSQL performance guides recommend. (code)

7. COPY BINARY

PostgreSQL’s COPY ... FROM STDIN (FORMAT BINARY) via PgBulkInsert. Instead of text CSV, it writes PostgreSQL’s native binary wire format — no parsing overhead on the server side. (code, generated)

8. DuckDB → PostgreSQL

Load data into an in-memory DuckDB table via DuckDB’s Appender API (extremely fast — ~850K rows/sec into DuckDB), then push to PostgreSQL via DuckDB’s postgres extension: INSERT INTO pg.table SELECT * FROM local_table. DuckDB uses COPY BINARY under the hood for the transfer. (code, generated)

9. Arrow → DuckDB → PostgreSQL

Build Apache Arrow columnar vectors in Java, register them with DuckDB as a virtual table (zero-copy), then push to PostgreSQL via the postgres extension. Skips the DuckDB staging table entirely. (code)

The Results

The interactive report below shows all batch sizes from 100 to 1,000,000 rows:

PostgreSQL Insert Benchmark

Comparing 9 insert methods across batch sizes from 100 to 1,000,000 rows

Throughput vs Total Rows

100 rows

Method	Time (ms)	Rows/sec	vs Best
Individual INSERT	9.0	11,057	10.0x slower
Batch INSERT	1.4	72,420	1.5x slower
Batch (rewrite=true)	1.4	69,433	1.6x slower
Multi-value INSERT	1.4	71,185	1.6x slower
UNNEST	1.3	74,810	1.5x slower
COPY CSV	0.9	110,549	fastest
COPY BINARY	2.0	51,234	2.2x slower
DuckDB -> PostgreSQL	3.0	33,531	3.3x slower
Arrow -> DuckDB -> PG	4.2	23,937	4.6x slower

1,000 rows

Method	Time (ms)	Rows/sec	vs Best
Individual INSERT	39.0	25,612	9.7x slower
Batch INSERT	6.8	147,246	1.7x slower
Batch (rewrite=true)	5.1	196,576	1.3x slower
Multi-value INSERT	7.9	127,238	2.0x slower
UNNEST	6.4	155,451	1.6x slower
COPY CSV	4.0	249,664	fastest
COPY BINARY	4.9	205,923	1.2x slower
DuckDB -> PostgreSQL	7.5	133,547	1.9x slower
Arrow -> DuckDB -> PG	10.9	91,756	2.7x slower

10,000 rows

Method	Time (ms)	Rows/sec	vs Best
Individual INSERT	266.0	37,589	16.5x slower
Batch INSERT	64.3	155,544	4.0x slower
Batch (rewrite=true)	36.1	276,876	2.2x slower
Multi-value INSERT	39.8	251,090	2.5x slower
UNNEST	40.5	247,087	2.5x slower
COPY CSV	32.2	310,479	2.0x slower
COPY BINARY	16.1	621,596	fastest
DuckDB -> PostgreSQL	40.4	247,228	2.5x slower
Arrow -> DuckDB -> PG	39.3	254,744	2.4x slower

100,000 rows

Method	Time (ms)	Rows/sec	vs Best
Individual INSERT	2,650.2	37,733	17.8x slower
Batch INSERT	633.3	157,907	4.2x slower
Batch (rewrite=true)	375.6	266,216	2.5x slower
Multi-value INSERT	386.2	258,964	2.6x slower
UNNEST	392.0	255,124	2.6x slower
COPY CSV	278.0	359,671	1.9x slower
COPY BINARY	149.1	670,830	fastest
DuckDB -> PostgreSQL	354.2	282,339	2.4x slower
Arrow -> DuckDB -> PG	290.4	344,363	1.9x slower

1,000,000 rows

Method	Time (ms)	Rows/sec	vs Best
Individual INSERT	25,494.3	39,225	18.2x slower
Batch INSERT	6,173.2	161,990	4.4x slower
Batch (rewrite=true)	3,423.6	292,091	2.4x slower
Multi-value INSERT	3,960.3	252,504	2.8x slower
UNNEST	4,124.8	242,437	2.9x slower
COPY CSV	2,774.5	360,420	2.0x slower
COPY BINARY	1,403.7	712,418	fastest
DuckDB -> PostgreSQL	3,274.8	305,362	2.3x slower
Arrow -> DuckDB -> PG	2,830.8	353,263	2.0x slower

System Information

Java	Java 25 (Temurin 25+36-LTS)
OS	Linux 6.8.0-100-generic
Arch	amd64
CPUs	24
Max Memory	7,956 MB
PostgreSQL	18 (TestContainers)
Warmup Runs	2
Measurement Runs	5

How They Scale

The performance characteristics change with data volume. At small sizes (100-1,000 rows), the overhead of COPY setup makes simpler methods competitive. COPY CSV actually wins below ~5K rows. But once you cross 10K rows, COPY BINARY pulls away and the gap widens linearly.

At 1M rows, COPY BINARY delivers 712K rows/sec — 2x faster than COPY CSV, 2.4x faster than reWriteBatchedInserts, and 18x faster than individual INSERTs.

The DuckDB Detour: What We Learned

The DuckDB approach was the most fun to benchmark. DuckDB is known for being heavily optimized, and we were curious whether routing data through its postgres extension could beat a direct COPY. The idea: spin up an in-memory DuckDB instance as a temporary buffer — no files, no persistence, just a fast columnar engine to stage data before pushing it to PostgreSQL.

DuckDB Appender path (method 8): DuckDB’s appender loads 1M rows into an in-memory table in ~1.1s (~935K rows/sec). But then the DuckDB postgres extension takes ~2.3s to push that data to PostgreSQL. Total: 3.3s. The bottleneck is the cross-engine transfer.

Arrow path (method 9): Building Arrow vectors directly and registering them as a virtual table with DuckDB (zero-copy, no staging table needed) is faster than the appender path (~635ms vs ~1.1s for 1M rows). DuckDB scans the Arrow memory directly. But the copy-to-PG step takes the same ~2.2s. Total: 2.8s.

Key insight: DuckDB’s postgres extension already uses COPY BINARY under the hood (we confirmed this by reading the source). So the DuckDB → PG transfer is doing the same thing as PgBulkInsert, but with additional overhead from the cross-engine bridge. Direct PgBulkInsert cuts out the middleman.

Where DuckDB shines is if your data is already in DuckDB (from a Parquet file, a CSV, a data pipeline). In that case, ATTACH + INSERT INTO is the most natural path and gives you COPY BINARY for free without any extra libraries. For data that starts in Java, going direct is faster.

Recommendations

For most applications: `reWriteBatchedInserts=true`

If you’re using JDBC (directly or through Spring/Hibernate), just add ?reWriteBatchedInserts=true to your connection URL. One parameter change, zero code changes, ~2.5x throughput improvement over naive batching. This is the best ROI optimization.

jdbc:postgresql://host:5432/db?reWriteBatchedInserts=true

For bulk ingestion: COPY BINARY via PgBulkInsert

If you’re ingesting thousands or millions of rows — ETL pipelines, IoT data, analytics ingestion, data migrations — use PgBulkInsert by Philipp Wagner. It’s a well-maintained Java library that handles the binary wire format, supports all PostgreSQL types (including arrays, UUIDs, JSONB, timestamps with timezone), and delivers ~700K rows/sec.

For COPY CSV users

If you’re already using COPY CSV (a common recommendation), know that switching to COPY BINARY roughly doubles your throughput. The difference is server-side parsing: CSV requires text → type conversion for every value, while binary sends data in PostgreSQL’s native format.

What about UNNEST?

UNNEST (INSERT INTO t SELECT * FROM unnest(...)) is often recommended as “faster than multi-value INSERT” because it reduces query planning overhead. In our benchmark with 9 columns, it was roughly equivalent to multi-value INSERT at most sizes. The advantage may be more pronounced with wider tables or simpler column types. Its real benefit is avoiding the 65K parameter limit — with 9 columns, multi-value INSERT maxes out at ~7,200 rows per statement.

How We Built This

The benchmark was built using SQG, a SQL-first code generator. SQG reads annotated .sql files and generates type-safe database access code for Java, TypeScript, and Python — queries, inserts, COPY BINARY appenders, DuckDB bulk insert appenders, all from a single SQL file.

In this benchmark, SQG generated the COPY BINARY appender (with PgBulkInsert mapper and row record), the DuckDB appender, the UNNEST insert, the individual INSERT, and the verification queries — all from queries.sql. The only hand-written insert methods are Batch INSERT and COPY CSV, which use raw JDBC.

Methodology

PostgreSQL 18 (alpine) via TestContainers 2.0.4
Java 25 (Temurin 25+36-LTS)
DuckDB 1.5.1, Apache Arrow 19.0.0, PgBulkInsert 9.0.0
Each method: 2 warmup runs + 5 measurement runs, median reported
Data verified after every insert (row count + first/last row spot checks)
All methods use a single connection (no parallel streams)
TestContainers runs PostgreSQL in Docker with default settings (no tuning)

Try It Yourself

git clone https://github.com/sqg-dev/sqg
cd sqg/examples/java-postgres-benchmark
just run

This generates the code from SQL files, runs the full benchmark, and writes an HTML report with interactive charts.

Credits

PgBulkInsert by Philipp Wagner — the library that makes COPY BINARY accessible from Java
DuckDB and its postgres extension
TestContainers

Have questions or want to challenge the methodology? Open an issue on GitHub.

SQG v0.10.0: Java Streams & List Type Support

Thu, 05 Mar 2026 00:00:00 GMT

SQG is a type-safe SQL code generator — you write .sql files with annotated queries, and it generates strongly-typed database access code for TypeScript and Java by introspecting your queries against real database engines at build time.

Here’s what’s new in v0.10.0.

Java: Stream-based result methods

Generated Java code now includes methods that return Stream<T> in addition to List<T>. This gives you lazy evaluation, easier composition with the standard library, and avoids materializing large result sets into memory when you don’t need to.

try (Stream<User> users = queries.getAllUsersStream()) {
    users.forEach(user -> process(user));
}

The stream holds a reference to the underlying ResultSet, so it needs to be closed after use — hence the try-with-resources.

Java: Better array/list field support

Array columns like TEXT[] or INTEGER[] are now handled correctly in generated Java code. Previously these types could produce incorrect mappings — they now resolve to proper List<String>, List<Integer>, etc.

DuckDB: List types in Appender

The DuckDB appender now supports list/array column types. If your table has a column like tags VARCHAR[], the generated appender method accepts the corresponding list type and writes it correctly using DuckDB’s bulk insert API.

Upgrade with npm install -g @sqg/sqg@0.10.0 or update your project’s dependency. Full source on GitHub. Try it out in the playground.

Discuss this on Hackernews.

PostgreSQL Support & Built-in Migration Tracking

Fri, 06 Feb 2026 00:00:00 GMT

SQG v0.8.0 brings two major features: improved PostgreSQL support for Java and a built-in migration runner that tracks which migrations have been applied.

Built-in Migration Tracking

Until now, SQG generated a getMigrations() method that returned raw SQL strings — you were responsible for tracking which ones had been applied. That meant writing your own migration runner or integrating an external tool.

With v0.8.0, you can now enable a built-in applyMigrations() method:

sqg.yaml

version: 1
name: my-app

sql:
  - files:
      - queries.sql
    gen:
      - generator: typescript/sqlite
        output: ./src/generated/
        config:
          migrations: true  # enable built-in migration tracking

Then in your application:

import Database from 'better-sqlite3';
import { MyApp } from './generated/my-app';

const db = new Database('app.db');

// One line — creates tracking table, checks what's applied, runs the rest
MyApp.applyMigrations(db);

const queries = new MyApp(db);

How It Works

The generated applyMigrations() method:

Creates a _sqg_migrations table if it doesn’t exist
Checks which migrations have already been applied for this project
Applies new migrations in order
Records each migration with a timestamp
Wraps everything in a transaction for safety

The tracking table uses a composite primary key of (project, migration_id), which means multiple SQG projects can share the same database without conflicts. The project name comes from the name field in your sqg.yaml.

// Default project name from sqg.yaml
MyApp.applyMigrations(db);

// Override for multi-tenant scenarios
MyApp.applyMigrations(db, 'tenant-123');

Supported Across All Generators

The migration runner works with every SQG generator:

Generator	Method
TypeScript/SQLite (better-sqlite3)	`MyApp.applyMigrations(db)`
TypeScript/SQLite (node:sqlite)	`MyApp.applyMigrations(db)`
TypeScript/SQLite (libSQL)	`await MyApp.applyMigrations(client)`
TypeScript/DuckDB	`await MyApp.applyMigrations(conn)`
Java/JDBC (any engine)	`MyApp.applyMigrations(connection)`
Java/DuckDB Arrow	`Analytics.applyMigrations(connection)`

Each implementation uses the appropriate transaction mechanism for its engine — BEGIN IMMEDIATE for SQLite, setAutoCommit(false) for JDBC, and so on.

Still Optional

The feature is entirely opt-in. Without config.migrations: true, SQG generates the same getMigrations() method as before. You can continue using external migration tools like Flyway, Liquibase, or your own scripts.

PostgreSQL Improvements

v0.8.0 significantly improves PostgreSQL support for the java/postgres generator.

User-Defined Types (ENUMs)

SQG now introspects PostgreSQL’s pg_type system catalog to resolve user-defined types. This means ENUMs work out of the box:

-- MIGRATE 1
CREATE TYPE task_status AS ENUM ('pending', 'active', 'completed', 'cancelled');

CREATE TABLE tasks (
    id SERIAL PRIMARY KEY,
    title TEXT NOT NULL,
    status task_status DEFAULT 'pending'
);

-- QUERY get_tasks_by_status
@set status = 'active'
SELECT id, title, status FROM tasks WHERE status = ${status}::task_status;

SQG resolves the ENUM OID from pg_type and generates a type-safe Java enum class with getValue() and fromValue() methods. Query parameters and results use the generated enum type directly instead of raw strings. See the Java + JDBC PostgreSQL documentation for details.

Array Types

PostgreSQL array columns like TEXT[] and INTEGER[] are now properly mapped to List<T> in Java:

CREATE TABLE tasks (
    id SERIAL PRIMARY KEY,
    tags TEXT[],
    priority_scores INTEGER[]
);

// Generated record
record GetAllTasksResult(Integer id, String title, List<String> tags, List<Integer> priorityScores) {}

for (var task : queries.getAllTasks()) {
    System.out.println(task.tags());            // [urgent, backend]
    System.out.println(task.priorityScores());  // [10, 20, 30]
}

TIMESTAMPTZ Support

TIMESTAMPTZ columns are now correctly mapped to OffsetDateTime (instead of LocalDateTime), preserving timezone information:

// TIMESTAMPTZ -> OffsetDateTime with UTC offset
record EventResult(Integer id, OffsetDateTime createdAt) {}

Automatic Testcontainers

If the SQG_POSTGRES_URL environment variable is not set, SQG now automatically starts a PostgreSQL container using Testcontainers. This makes it easy to get started without installing PostgreSQL locally — just have Docker running:

# No env var needed — SQG starts a container automatically
sqg sqg.yaml

For CI/CD or production builds, set the environment variable to point to your PostgreSQL server:

export SQG_POSTGRES_URL="postgresql://user:password@localhost:5432/mydb"
sqg sqg.yaml

Get Started

Install or update SQG:

pnpm add -g @sqg/sqg@latest

Enable migration tracking by adding config.migrations: true to your generator config. Check out the updated SQL Syntax Reference and generator documentation for full details.

Have questions or feedback? Open an issue on GitHub.

SQLite Driver Benchmark: Comparing better-sqlite3, node:sqlite, libSQL, Turso

Mon, 19 Jan 2026 00:00:00 GMT

Choosing the right SQLite driver for Node.js can impact your application’s performance.

We ran performance tests comparing better-sqlite3, node:sqlite, libSQL, and Turso across common database operations. Here’s what we found.

The Four SQLite Options for Node.js

better-sqlite3

This library has been tested in production for years, offering excellent performance through a synchronous API. The synchronous API makes it very performant and easy to use, and is perfect for fast queries.

→ GitHub better-sqlite3

node:sqlite

Node.js 22+ includes a built-in SQLite module (still experimental). It provides zero-dependency SQLite access with a synchronous API similar to better-sqlite3, and also an asynchronous API.

→ Node.js SQlite Documentation

libSQL

An open-source fork of SQLite created by the Turso team. It provides an async API and supports both local database files and remote libSQL/Turso servers. Fully compatible with the original SQLite (file format, API)

→ libSQL TypeScript

Turso

Turso is a SQLite compatible database written in Rust. Currently still in beta.

→ Turso for Javascript

Benchmark Methodology

We tested all four drivers with identical queries. A simple scenario with a user and posts table.

10,000 users and 500,000 posts (50 per user)
Optimized pragma settings (WAL mode, 64MB cache, memory-mapped I/O)
Various query patterns: simple selects, indexed lookups, JOINs, aggregates, inserts, updates

Note: better-sqlite3 and node:sqlite use synchronous APIs, while libSQL and Turso use async/await.

SQLite Configuration

All databases used these optimized settings:

PRAGMA journal_mode = WAL;       -- Write-Ahead Logging
PRAGMA synchronous = NORMAL;      -- Balance safety/speed
PRAGMA cache_size = -64000;       -- 64MB cache
PRAGMA temp_store = MEMORY;       -- Temp tables in memory
PRAGMA mmap_size = 268435456;     -- 256MB memory-mapped I/O

Results

SQLite Driver Benchmark Report

Comparing better-sqlite3 vs node:sqlite vs libsql vs turso (baseline: node:sqlite)

System Information

Node.js Version	v25.3.0
Platform	linux
Architecture	x64
CPU	12th Gen Intel(R) Core(TM) i9-12900K
CPU Cores	24
Total Memory	31.07 GB

Summary

Operation	better-sqlite3	node:sqlite	libsql	turso	Winner	vs node:sqlite
getAllUsers	360 ops/s	268 ops/s	50 ops/s	104 ops/s	better-sqlite3	1.34x
getUserById	1,223,260 ops/s	1,073,001 ops/s	61,093 ops/s	707,859 ops/s	better-sqlite3	1.14x
getUserByEmail	557,631 ops/s	457,659 ops/s	49,510 ops/s	233,913 ops/s	better-sqlite3	1.22x
countUsers (pluck)	538,031 ops/s	398,431 ops/s	108,632 ops/s	5,593 ops/s	better-sqlite3	1.35x
getPostsByUser	1,090,293 ops/s	980,550 ops/s	47,304 ops/s	414,672 ops/s	better-sqlite3	1.11x
getPublishedPosts (JOIN)	27 ops/s	27 ops/s	54 ops/s	7 ops/s	libsql	1.98x
getPostWithAuthor (JOIN :one)	477,271 ops/s	379,911 ops/s	32,433 ops/s	236,297 ops/s	better-sqlite3	1.26x
countPostsByUser (pluck)	1,151,783 ops/s	689,478 ops/s	111,824 ops/s	377,235 ops/s	better-sqlite3	1.67x
insertUser	53,693 ops/s	41,291 ops/s	28,385 ops/s	63,017 ops/s	turso	1.53x
updatePostViews	136,399 ops/s	97,956 ops/s	53,598 ops/s	59,273 ops/s	better-sqlite3	1.39x

Key Findings

better-sqlite3 is the fastest for most operations, with node:sqlite second
Turso has a surprisingly slow query for countPostsByUser (better-sqlite3 is almost 100x faster here). I did not investigate why this is, it might be that the Turso database like many others (eg Postgresql) needs to scan the full table in order to count the number of rows and has no fast handling for this special case.

Benchmark Implementation

The benchmark is implemented using SQG, a SQL to code generator.

One advantage of using a code generator like SQG is that you can switch between SQLite drivers without rewriting your queries. SQG generates type-safe code for all four drivers from the same SQL file:

# sqg.yaml - generate code for multiple drivers
sql:
  - files:
      - queries.sql
    gen:
      - generator: typescript/sqlite/better-sqlite3
        output: ./src/db-better-sqlite3.ts
      - generator: typescript/sqlite/node
        output: ./src/db-node-sqlite.ts
      - generator: typescript/sqlite/libsql
        output: ./src/db-libsql.ts
      - generator: typescript/sqlite/turso
        output: ./src/db-turso.ts

This makes it easy to benchmark with your actual queries and switch drivers by changing imports.

Try It Yourself

The benchmark code is available in our examples repository:

git clone https://github.com/sqg-dev/sqg
cd sqg/examples/typescript-sqlite-benchmark
pnpm install
pnpm generate
pnpm bench

This will generate an HTML report with the results table shown above.

Conclusion

I think for most applications, better-sqlite3 remains the best choice.

Benchmarks generated using SQG. Have questions? Open an issue on GitHub.

Introducing SQG

Wed, 17 Dec 2025 00:00:00 GMT

We’re excited to announce SQG (SQL Query Generator), a tool that generates type-safe database access code from your SQL queries.

The Problem

Writing database code means maintaining SQL queries and matching TypeScript/Java types. When schemas change, you update both—and hope nothing breaks. ORMs abstract SQL away, but what if you want to write SQL directly while keeping type safety?

The Solution

SQG reads annotated .sql files, executes queries against real databases to introspect column types, and generates fully-typed wrapper code.

Write your SQL with simple annotations:

-- MIGRATE createUsersTable
CREATE TABLE users (id INTEGER PRIMARY KEY,
                    name TEXT NOT NULL,
                    email TEXT);

-- QUERY getUserById :one
@set id = 1
SELECT id, name, email FROM users WHERE id = ${id};

-- QUERY getUsers
SELECT id, name, email FROM users;

-- EXEC insertUser
@set name = 'John'
@set email = 'john@example.com'
INSERT INTO users (name, email) VALUES (${name}, ${email});

SQG generates type-safe code:

export class Queries {
  getUserById(id: number): { id: number; name: string; email: string | null } | undefined
  getUsers(): { id: number; name: string; email: string | null }[]
  insertUser(name: string, email: string): RunResult
}

Key Features

Type-safe by design - Column types inferred from your actual database
Multiple databases - SQLite, DuckDB, and PostgreSQL
Multiple languages - Generate TypeScript or Java from the same SQL
DBeaver compatible - Develop queries in DBeaver, generate code from the same file
Zero runtime overhead - Generated code is plain function calls

Get Started

Install SQG:

pnpm add -g @sqg/sqg
pnpm approve-builds -g  # needed for sqlite dependency

Create a sqg.yaml config and your SQL file, then run sqg sqg.yaml. Check out the Getting Started guide for details.

We’d love your feedback! File issues and feature requests on GitHub.

SQG - Compile SQL to Type-Safe Code | Blog

I Benchmarked 9 Ways to Insert Data Into PostgreSQL From Java. COPY BINARY Won by a Landslide.

The Setup

The Methods

1. Individual INSERT (the naive approach)

2. Batch INSERT (addBatch / executeBatch)

3. Batch INSERT with reWriteBatchedInserts=true

4. Multi-value INSERT (hand-crafted)

5. UNNEST

6. COPY CSV

7. COPY BINARY

8. DuckDB → PostgreSQL

9. Arrow → DuckDB → PostgreSQL

The Results

PostgreSQL Insert Benchmark

Throughput vs Total Rows

100 rows

1,000 rows

10,000 rows

100,000 rows

1,000,000 rows

System Information

How They Scale

The DuckDB Detour: What We Learned

Recommendations

For most applications: reWriteBatchedInserts=true

For bulk ingestion: COPY BINARY via PgBulkInsert

For COPY CSV users

What about UNNEST?

How We Built This

Methodology

Try It Yourself

Credits

SQG v0.10.0: Java Streams & List Type Support

Java: Stream-based result methods

Java: Better array/list field support

DuckDB: List types in Appender

PostgreSQL Support & Built-in Migration Tracking

Built-in Migration Tracking

How It Works

Supported Across All Generators

Still Optional

PostgreSQL Improvements

User-Defined Types (ENUMs)

Array Types

TIMESTAMPTZ Support

Automatic Testcontainers

Get Started

SQLite Driver Benchmark: Comparing better-sqlite3, node:sqlite, libSQL, Turso

The Four SQLite Options for Node.js

better-sqlite3

node:sqlite

libSQL

Turso

Benchmark Methodology

SQLite Configuration

Results

SQLite Driver Benchmark Report

System Information

Summary

Key Findings

Benchmark Implementation

Try It Yourself

Conclusion

Introducing SQG

The Problem

The Solution

Key Features

Get Started

2. Batch INSERT (`addBatch` / `executeBatch`)

3. Batch INSERT with `reWriteBatchedInserts=true`

For most applications: `reWriteBatchedInserts=true`